Method of cleaning textile print wash blankets



y 29, 956 w. c. ROSS ET AL 2,747,506

METHOD OF CLEANING TEXTILE PRINT WASH BLANKETS Filed Feb. 6, 1952 Inventors William 0. Ross Alec M. Niconchuk Affo rney United States Patent fiice 2,747,506 Patented May 29, 1956 METHOD OF CLEANING TEXTILE PRINT WASH BLANKETS William C. Ross, Winchester, and Alec W. Niconchuk, Peabody, Mass., assignors to W. R. Grace & Co., a corporation of Connecticut Application February 6, 1952, Serial No. 270,188

4 Claims. (Cl. 101-424) This is a division and continuation-in-part of our application for patent Serial No. 215,358, filed March 13, 1951, now U. S. Patent No. 2,723,932. The parent specification discloses a textile printing wash blanket having a working surface formed from a linear polymeric, high tensile strength synthetic yarn such as formed from elastic cold drawn fibers of a synthetic linear crystalline high polymer, e. g., nylon, polyacrylonitrile and a polyester produced by reaction of teraphthalic and ethylene glycol joined to a flexible and compressible backing layer. In contradistinction to prior wash blankets where the surplus color is merely spread on an impermeable surface, these blankets absorb and hold surplus color in the interfiber capillary spaces of the yarn. They are able to pick up and carry away much larger quantities of the color which is driven through the goods as they are printed or which is emptied onto the blanket by the flooded engravings which extend beyond the selvage of the goods. Despite the large charges of color which this blanket can handle without danger of edge and body flushing, it is, when conventional colors are used, practically entirely freed of this charge of color merely by flooding the blanket with warm water and then passing it between squeeze rolls.

There has, however, been a growing use of pigment colors. These newer textile coloring pastes, as contrasted with the dyes thickened with water-swellable gums which are the conventional coloring materials, are complex dispersions, One phase consists of a heat-curing type resin dissolved in solvent. The other phase is water. Both water-in-oil and oil-in-water emulsions are used. The colors are usually suspensoids in the dispersion. Accordingly, depending upon the type of emulsion which is utilized, the resin solution is either the external or the internal phase.

Both types of pigment colors behave in the same way whenever a thin film is spread on the textile goods or on the blanket; the emulsion breaks and a Varnish-like sticky film of pigmented resin is deposited which, if it is not removed, will build up on the blanket as a horny, frangible scale because the resin cures as the blanket passes over the dryer cans. Flooding a blanket with water and then squeezing it is ineffective in keeping a blanket clean when pigment colors are used.

As disclosed in the parent specification, We discovered that our new blankets could be flushed free of pigment colors as they passed through the squeeze rolls of a blanket washer if the fibers of the linear polymer which form the working layer carried thin films of a detergent on their surface before they came in contact with the pigment colors at the printing station. Then when the color-smeared flight of the blanket entered the blanket washer, was flooded with water, brushed and squeezed, the pigment colors were flushed out of the working layer.

In the drawings:

Figure 1 is a diagrammatic elevation of a textile range showing the printing station, the washing apparatus and the blanket drying cans.

Figure 2 is a diagrammatic elevation of the same textile range showing the modifications employed when pigment emulsion colors are being run.

In Figure l, the blanket 23 loops around the bed roll 24. The goods 25 run over the blanket 23 and beneath the color rolls 2626. The out-running flight of the blanket which now is smeared with color loops around the washer roll 27. Rotary brushes 2828 drenched with water from the spray pipes 2929 brush the working surface of the blanket. The blanket is squeezed between washer roll 27 and squeeze roll 31 and then is flooded with a detergent solution fed to the surface of the blanket through the drip pipe 32, which is supplied from the stock tank 33. The blanket is again squeezed between washer roll 27 and squeeze roll 34, then passes over the drying cans 35-35 and returns to the printing station. Sometimes roll 34 can be omitted, and the detergent solution then is run onto the blanket just ahead of rolls 27 and 31. The thin film of detergent which is left on the yarns after squeezing dries as the blanket passes over the drying cans. If the film is properly applied, color will be squeezed out of the yarns as the blanket passes through the bite between the rolls 27 and 31. Satisfactory detergents are soap (1% sodium oleate in water), pine oil emulsion, several proprietary soapdetergent builder combinations, a proprietary pine oil substitute known as Terposol, and bentonite-sodium pyrophosphate suspensions.

in using emulsion colors, the important precaution is to take care that the hydrophilic detergent substance coats the individual fibers before any of the varnish-like resin deposit comes in contact with the surface of the blanket. If this precaution is taken, the emulsion colors may be cleaned from the blanket in a highly satisfactory manner.

As soon, however, as the efiiciency and efiectiveness of this method of cleaning pigment colors had been shown by mill runs, textile colorists began raising the amount of resin present in pigment color pastes. did this to eliminate a minor amount of crocking, which hitherto had been a characteristic of pigment colors.

Shortly, the concentration of resin in the so-called high cut color pastes became so high that the soap or other detergent films placed on the blanket, as we described above, could not remove all of it.

In examining the film of color which was left on the blanket, when high cut pigment colors were used, it was noted that the color, particularly on the margins of the blanket beyond the selvage of the goods was laid down almost in a continuous coat as if the blanket had been varnished. The low cut colors did not form such an unbroken, continuous film. They emulsified in soapy water with reasonable ease and 'were easily brushed off the blanket. The high cut colors were not easy to emulsify.

Printing blankets, which are usually about forty yards long, run, ordinarily, from fifty to one hundred and ninety yards a minute. Only two to three yards of blanket are in the blanket washer at any one time. Thus, the time during which the blanket must be completely cleaned in the washer varies from less than a second to a bit over two seconds. It seemed probable to us, therefore, that the washing fluid did not have time to penetrate the heavier, varnish-like film, emulsify it and carry it away then seemed probable that if we could keep an impermeable film of resin from forming, possibly by keeping the film in a pulpy, gelatinous condition, the combined action of the brushes and the washing fluid would They- 3 remove the deposit in the very short time that was available.

To modify the color film in this manner, we sought for a material which would keep the pigment color films soft and gelatinous, would not be chemically or physically dc structive to the surface or body of the blanket, would not volatilize as the blanket was dried, and which, together with the pigment color, could be easily dispersed by brushing and washing. We discovered that the addition of relatively small amounts of petroleum compounds known as rubber extenders to a pigment color paste prevented a film of pigment color from hardening, no matter how long it was heated at a temperature sufiiciently high to cure the resin. Applying this discovery to the problem in hand, we found that, if a film of rubber extender was left on the fibers of the working surface of the blanket before they came in contact with pigment colors and if the color laid down in printing was wet with such a material, the pigment colors, even in high cuts, did not harden, but remained in a gelled condition. The gel could be removed from the blanket even if the blanket was heated for a long time.

A possible explanation for this effect is that the fibers which form the Working face of the blanket are essentially hydrophobic and apparently are preferentially wet by the rubber extender even in the presence of a soap solution. In comparing the feeling of a blanket which has been wet with a solution of a rubber extender before any color has been spread on it with a blanket not so treated, one notices a distinct change. The blanket treated with the extender even though it has been washed with soap feels smooth and slippery. The other feels cloth-like and harsh. If the extender is absorbed on the fiber, then the color does not come into contact with the actual surface of the fiber itself. Moreover, if the amount of extender left on the fiber is something more than a monomolecular absorbed layer, as is possible, then this amount of extender could be effective in gelatinizing the film of color at least to the extent of gelatinizing the immediately adjacent molecules of resin.

Despite the gelatinization of the color, emulsification of the color in the wash water in the time available remained a problem.

It was finally discovered that the addition of an emulsifying agent to the rubber extender not only maintained the pigment color in the soft gelatinized condition, but caused it to disperse so that it was effectively washed off in a normal textile blanket washer at normal printing speeds. Tests made with various oil soluble emulsifying agents on various proprietary pigment colors showed that the agents varied in effectiveness, but, generally speaking, one to two per cent of emulsifying agent calculated on the weight of the resin content of the pigment color was sufiicient to cause rapid dispersion of the color film.

The amount of emulsifying agent required is directly related to the amount of color to be removed. This varies from pattern to pattern, change in goods, and change in color.

The-following proportions are adjusted for average experience. They must be varied by the printer as occasion demands. It can be seen that, if the amount of color to be removed is very small, it may be necessary to raise the proportion of extender, whereas if the amount of color is very large, it may be necessary to raise the proportion ofemulsifying agent, but in'no case should more than one part ofemulsifying agent .to two parts'of extender be used. The solution may be diluted with volatile hydrocarbon further. than the figures given if the amount of non-volatile matter to be applied to the blanket is very small, thereason being that there is a low limit to the amount ofliquid which a pad roll will apply as a continuous film. On the high side; no more than 4 lbs. of non-volatile material per 1000 sq; yds; of blanket shouldbe applied.

For the usual range of patterns, eight to fifteen per cent of emulsifying agent calculated on the weight of the rubber extender in the cleaning solution adds an effective amount of emulsifying agent to the resin film on the blanket when the solution is padded on the color smeared blanket after it leaves the printing station.

Since several colors are run on the blanket at the same time, and some of these colors may be oil-in-water while others may be water-in-oil emulsions, we found it advantageous to use as the emulsifyingagents those which not only are oil soluble, so that they can be brought into solution in the rubber extender, but those which are soluble in water as well. Oil solubility of the emulsifying agent. is essential in order to dissolve the emulsifier in the extender solution. Oil and water solubility of the emulsifying agents adds greatly to the convenience and range of elfectiveness of the cleaning solution.

Rubber extenders are derived from certain residues of oil refining. The nature and the manufacture of these products vary to a certain degree because of the nature of the crude and the method of refining which may be used. They react with sulphur and may be covulcanized With rubber. For further information on materials of this class, see United States Patent No. 2,180,367 to Fritz Rostler et al. and the article of Fritz S. Rostler in Rubber Age, vol. 69, No. 5, page 559, of August 19, 1951. Weprefer to use rubber extenders with viscosities above 7000 Saybolt seconds at 100 F. Lower viscosity extenders may show running and wicking in the working face of the Cleaning solution Parts by weight Rubbert extender Emulsifying agent 2 10 Low rubber solvency hydrocarbon solvent 3 800 The following rubber extenders have been found to be suitable: Nuso 125. supplied by Esso Standard Oil Company. Cn-casol 2XH, supplied by Sun Oil Company. Dutrex 20, supplied by Shell Oil Company. 7

The following emulsifying agents have been found to be suitable: Brij 30 (said to be polyoxy'ethylene lauric alcohol) supplied 7 by Atlas Powder Company. heutronyx 834 (said to be a fatty acid ester ofa polyether alcohol) supplied by Onyx Oil & Chemical Corp. Polyethylene glycol 400 di laurate (said to be the lauric acid (ii-ester of polyethylene glycol) supplied by Glyco Products.

FA high solvency Stoddard solvent such as Varsol #2 supplied by Esso Standard Oil Company.

This solution is padded on the blanket after it'haspicked.

up color as near to the printing station as the installation cond1tions of the printing range will permit.

Padding solution for use subsequent to squeeze-di'yi'rig't he blanket and before heat-drying it Parts by weight Rubber extender 9 0 Emulsifying agent l0 Hydrocarbon solvent 1600 The amount of the cleaning solution required toclean the blanket depends upon the amount of color' to be removed. Fromone to three gallons padded onto the dirty blanket for each thousand square yards of blanket usually sufiicient. V V V The padding solution is padded onto the blanket" just as it leaves the squeeze dryer of the washingapparatus' and before the blanket passes over the heated drying cans. In the heat drying step, whatever water remains and the solvent are largely driven oif. A' substantially dry blanket passes into the printing station.

One gallon of padding solution spread over 1000 square yards of blanket is ordinarily ample to prevent any buildup of color on the blanket. The skill and care of the printer are the controlling factor at this point. A few printers can, on selected patterns, adjust their Washer so carefully that the blanket will carry through enough extender to remain clean on mill runs without padding more extender onto the blanket after it has been washed, but there are not many who exert this degree of care or skill. The practice which we recommend, namely, padding on a dilute solution after washing, has latitude enough so that an ordinary printer can keep his blanket clean.

Blankets designed for use with pigment colors are made of oil and solvent resistant materials. These solutions have very little effect on their strength or wearability; the blankets run their expected service life.

A printing range adapted to clean pigment colors by our improved process is diagrammatically illustrated in Figure 2. Those parts of the printing range common to both Figures 1 and 2 are shown on Figure 2 with the same reference numbers as on Figure 1, but with primes added for identification. Somewhere in the outrunning flight of the blanket, and preferably located as near to the printing station as is possible, the dirty blanket runs under a padding roll 36 which lays a thin film of the extender solution directly on the colored surface. The solution runs from the tank 37 through the pipe 38 through the flow control valve 39 and to a V box weir 41 which extends along the length of the padding roll 36. By adjusting the valve 39, drops of the solution flow over the weir and fall onto the padding roll.

The outrunning flight of the blanket 23 then passes to the washing station. It is advantageous to have the padding roll located as far from the Washing station as is possible, since the longer the solution remains in contact with the color which is on the surface of the blanket, the softer and more gelatinous the color becomes and the easier it is to remove it by washing. At the washing station, the blanket loops around the main wash cylinder 27' and meets an array of several rotary brushes, some of which run in a direction counter to that of travel of the blanket. Brushes 47 and 49 ordinarily run dry and turn counter to the direction of blanket travel. They are provided with water jets 48 and 50 directed on the bristles of the brush so that from time to time the bristles may be washed free of any accumulations of color. Brushes 51 and 53 rotate in opposite directions. Their bristles dip into the soap pans 52 and 54 so that the surface of the blanket is scrubbed with a soap solution at this point. Brush 55 runs much faster than the rate of travel of the blanket and counter to its direction of movement. Beyond the brush 55, a soap solution is flooded onto the blanket by flowing through the drip pipe 32 which is supplied from the soap tank 33. The excess soap solution which flows down over the surface of the blanket is brushed through brush 55 and maintains the soap solution level in the soap pans 52 and 54. Roll 34 is preferably a rubber covered squeeze roll which, desirably, is adjusted by an air cylinder so that the squeeze pressure on the blanket may be quickly and accurately controlled. A second padding roll 42 is located just beyond the squeeze roll on the in-running flight of the blanket. It is supplied with a dilute solution of the extender which flows from the tank 43 through the control valve 44 and the V weir box 45 which extends along the length of the padding roll. The blanket then passes over the series of dry cans 35', which are preferably placed in a casing 57 which is vented to the outside of the buiding and is supplied with fresh air through the blower 56. The dried blanket 23 enters the printing station, passing under the goods and under the color rolls 26', 26', and loops around the bed roll 24' of the printing press. With the valves adjusted so that from one to three gallons of cleaning solution are padded ontothe blanket by the roll 36 and approximately one gallon of padding solution is padded onto the blanket by the roll 42, and the squeeze roll pressure adjusted so that the blanket feels quite dry as it leaves the squeeze roll, the machine will operate throughout long runs on pigment colors and clean the blanket properly.

The resins which are used to bond the pigments onto the fibers of the goods are quite varied. Some are ureaformaldehyde. Some are melamine resins. Some are modified alkyds. But, at the present time, the color purveyors appear to be using large quantities of both the urea-formaldehyde and the melamine resins. Most colors are proprietary products with undisclosed formulae. The precise nature of the resin is rarely known by the textile printer and often changes.

From time to time, entirely new types of resin appear in the proprietary color formulations. Before risking an expensive blanket to an unknown formula, we suggest that the color be tested for washability in the following manner:

A small evaporating dish is smeared with the color paste, and a few drops of the extender solution are added to the smear. The evaporating dish is then placed in an oven maintained at a temperature high enough to drive off the volatile solvent and to cause the resin to cure. If it is found that the resin has not cured in the presence of the extender solution, but remains gelatinous, then it is reasonably certain that the color can be washed oif the blanket in the manner which we describe.

We have conducted tests with a very large number of representative pigment colors sold to the textile printing industry, and so far have found none which have not re mained soft and easily displaced.

Our experience in experimental runs conducted on commercial scales has successfully demonstrated that blankets may be successfully washed and cleaned when high cut resin emulsion colors are used and that long runs without color buildup either in or on the blanket always result when the practice set forth in the present specification has been followed.

Blankets faced with solvent resistant rubber compounds are also widely used. Since their surfaces are impermeable, they do not have the capacity for carrying large charges of color which is characteristic of the blankets described in our parent specification. These rubber faced blankets, also, may be cleaned of pigment colors in a highly satisfactory manner by the process we have just described.

We claim:

1. The method of continuously cleaning an endless textile print wash blanket on a printing range which includes as continuous steps working into the inter-fiber space of the Working face of a textile print blanket having a working face composed of a textile layer formed from elastic cold-drawn fibers of a synthetic, linear, crystalline, high polymer, said fibers being essentially insoluble in and impermeable to textile printing colors and water, a solution of a liquid petroleum hydrocarbon rubber extender in a low rubber solvency volatile liquid hydrocarbon, drying the blanket to leave a substantially dry film of the rubber extender on the face and fibers thereof, passing the dry blanket through the printing station and depositing textile coloring matter on said dried film on the working face thereof, flooding the blanket with water and passing the blanket under brushes to remove surface color from the blanket, re-applying the rubber extender solution, and repeating the succession of steps continuously during the operation of the printing range.

2. The method of continuously cleaning an endless textile print wash blanket on a printing range which includes as continuous steps applying to a textile print blanket having a working face composed of a textile layer formed from elastic cold-drawn fibers of a synthetic, linear, crystalline, high polymer, said fibersbeing essentially insoluble in and impermeable to textile printing, colors and water, a solution of a water dispersible, film forming detergent, squeezing the blanket between a set of squeeze rolls, working a solution of a liquid petroleum hydrocarbon rubber extender in a low rubber solvency volatile liquid hydrocarbon into the inter-fiber space of the working face of the blanket, drying the blanket to leave a substantially dry film of the detergent and of the rubber extender on the face and fibers thereof, pasing the dry blanket through the printing station and depositing textile coloring matter on said dried film on the Working face thereof, flooding the blanket with water and passing the blanket under brushes to remove surface color from the blanket, reapplying the detergent solution, and repeating the succession of steps continuously during the operation of the printing range.

3. The method of removing uncured pigment colors which have been deposited upon the surface of an endless textile print blanket having a Working face composed of a synthetic, linear, crystalline high polymer which comprises the following steps: first working into the interfiber spaces of the working face of the blanket a solution of a liquid petroleum hydrocarbon rubber extender and an oil soluble non-ionic emulsifying agent in a low rubber solvency volatile liquid hydrocarbon, driving the hydrocarbon oif by heating the blanket, passing the blanket through the printing station and depositing a pigment color thereon, depositing a film of the said extender solution on the color smeared blanket, Wet-brushing the blanket in the presence of a water solution of soap to remove the pigment color, applying a solution of soap to the washed blanket immediately in advance of a squeeze roll to leave a film of soap on the fibers of the Working surface of the blanket after squeezing, and continuously repeating the steps enumerated.

4. The method of removing uncured pigment colors from the surface of an endless textile print blanket which comprises first spreading on the surface of the blanket a solution of a liquid petroleum hydrocarbon rubber extended having a viscosity above 7000 'Saybolt seconds at F. and a non-ionic, oil soluble emulsifying'agent dissolved in a low rubber solvency volatile liquid hydrocarbon, removing the volatile hydrocarbon, thereafter running the blanket through the printing station of a textile printing range and depositing pigment'color on the treated surface, laying a film of the said extender solution directly on the deposited pigment color to keep the color soft, running the blanket to the washing station of the textile range, scrubbing the blanket in soap solution, roll squeezing the blanket to remove the excess cleaning solution, but leaving a protective film on the surface of the blanket, drying the blanket, and thereafter repeating as continuous steps running the blanket through the printing station, depositing color on the blanket, laying a film of extender solution on the deposited color, scrubbing the blanket in soap solution, squeezing the blanket, and drying the blanket during the operation of the printing range.

References Cited in the file of this patent UNITED STATES PATENTS 2,080,133 Jenkins May 11, 1937' 2,175,051 Bromley Oct. 3, 1939 2,180,367 Rossler et al. Nov. 21, 1939 2,222,143 Farnsworth et al. Nov. 19, 1940 2,252,554 Carothers Aug. 12, 1941 2,328,586 Ross Sept. 7, 1943 2,335,782 'McMordie et al Nov. 30, 1943 2,404,350 Carlson et al July 23, 1946 2,410,415 Jones Nov. 5, 1946 2,434,013 Ross Jan. 6, 1948 FOREIGN PATENTS 233,831 Switzerland Nov. 16, 1944 OTHER REFERENCES Davis et al.: Bentonite; Bureau of Mines, Paper 438, published 1928 by Government Printing Oflice Only page 35 made of record. (Copy available in Division 17.) 

1. THE METHOD OF CONTINUOUSLY CLEANING AN ENDLESS TEXTILE PRINT WASH BLANKET ON A PRINTING RANGE WHICH INCLUDES AS CONTINUOUS STEPS WORKING INTO THE INTER-FIBER SPACE OF THE WORKING FACE OF A TEXTILE LAYER FORMED FROM ELASTIC ING FACE COMPOSED OF A TEXTILE LAYER FORMED FROM ELASTIC COLD-DRAWN FIBERS OF A SYNTHETIC, LINEAR, CRYSTALLINE, HIGH POLYMER, SAID FIBERS BEING ESSENTIALLY INSOLUBLE IN AND IMPERMEABLE TO TEXTILE PRINTING COLORS AND WATER, A SOLUTION OF A LIQUID PETROLEUM HYDROCARBON RUBBER EXTENDER IN A LOW RUBBER SOLVENCY VOLATILE LIQUID HYDROCARBON, DRYING THE BLANKET TO LEAVE A SUBSTANTIALLY DRY FILM OF THE RUBBER EXTENDER ON THE FACE AND FIBERS THEREOF, PASSING THE DRY BLANKET THROUGH THE PRINTING STATION AND DEPOSITING TEXTILE COLORING MATTER ON SAID DRIED FILM ON THE WORKING FACE THEREOF, FLOODING THE BLANKET WITH WATER AND PASSING THE BLANKET UNDER BRUSHES TO REMOVE SURFACE COLOR FROM THE BLANKET, RE-APPLYING THE RUBBER EXTENDER SOLUTION, AND REPEATING THE SUCCESSION OF STEPS CONTINUOUSLY DURING THE OPERATION OF THE PRINTING RANGE. 